Tillage research reveals new insights into Septoria’s modus operandi

Tillage research undertaken by scientists at Rothamsted Research has shed new light on how the fungus Septoria tritici causes the premature death of wheat leaves, leading to the ultimate reduction in tillage crop yields.

The work was undertaken in collaboration with partners from Syngenta. It entailed the use of new technologies, which measured gene activity within the fungus.

This, in turn, allowed the research team to identify the various stages of fungal attack in ways that had not been technically possible up to this point.

The study has provided clear evidence for a manipulation of plants’ ability to defend themselves at different stages of infection. While plant defences were supressed during early infection the actual appearance of disease symptoms on leaves involved a clear activation of plant defences.

This is counter intuitive to what one would expect and suggests that Septoria tricks wheat into a premature form of defence involving cellular suicide as it attempts to limit pathogen spread.

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However, the fungus reproduces itself well within this tillage environment. This can be considered a form of eventual hijack of the wheat defence response.

“There was already evidence from previous work that Septoria did something to manipulate wheat’s defences,” said Dr Jason Rudd, lead scientist at Rothamsted Research.

“Our work now provides the clearest data so far that the pathogen must both initially suppress and then eventually activate plant defence during the course of successful infection.

“The many new Septoria genes, wheat genes and biochemicals identified in this study, provide an unparalleled resource for the development of tools that will support early identification of the disease and its subsequent management.”

Professor Kim Hammond-Kosack, leader of the wheat pathogenomics team at Rothamsted Research, said that the interactions now identified between Septoria and its plant host should reveal whether other fungal species also ‘hijack’ the same or other plant defence responses to benefit their reproductive potential within tillage crops.